1. Field of Invention
The present invention relates to fluids and more particularly to the mixing of fluids with an array of fluid ducts.
2. Description of the Prior Art
Manufacturers have resorted to a variety of devices and processes in order to physically mix or chemically react starting ingredients in the production of specific end products. Very often after a process has been evolved, a concerted effort is expended in improving the process in order to improve on the profitability of such a process. One collection of apparatus and techniques used in the manufacture of particulate solids is described in U.S. Pat. No. 3,499,476 entitled Spray Drying of Liquids to Form Particulate Solids. Fundamentally, the invention is directed toward improving the rate at which the certain solids can be manufactured and involves the use of three concentric spray rings which direct a working medium passing therethrough at an angle to the overall flow axis of the apparatus. Control of the spray pressures and the resulting cone pattern provides the improved performance.
A structurally different device which is initially suggestive of a plurality of nozzles for expanding gas in a direction which is not parallel to the overall flow axis is shown in U.S. Pat. No. 3,860,885 entitled Gas Laser Expansion Nozzles. At the heart of the invention is a plurality of nozzles for expanding gas to supersonic velocity with each nozzle having a throat region which is offset from the throat region of each adjacent nozzle. The expansion surfaces which define each nozzle are formed on elements which are asymmetric, although each nozzle is actually a two dimensional nozzle having an axis of symmetry and a skewed exit plane. The device is not used primarily to mix or react fluids, rather the purpose of having the nozzle throat offset is to avoid having the downstream shock waves from each of the nozzles reinforce one another, a concept very useful in gas laser systems.
Another invention having structure to induce mixing is described in U.S. Pat. No. 3,671,882 entitled Apparatus for Mixing Gas in a Fluid Mixing Laser. In this system, a first gas is flowed through a conduit having a plurality of hollow airfoil sections perpendicular to the flow. Interconnecting the airfoils is a series of tubular conduits containing small holes such that a second gs can be introduced into the main stream through the conduits essentially throughout the entire volume of the main stream, thereby permitting relatively quick and complete chemical reaction between the primary stream and the admixed gas. The system is considered applicable to chemical laser devices wherein rapid and complete mixing of the reactants is desired in order that the excited reaction species can be more fully exploited before natural processes deplete the usefulness of the reacted species.
In U.S. Pat. No. 3,174,282 entitled Asymmetrical Jet Nozzle Noise Suppressor, the inventor discloses an apparatus intended to reduce the characteristic noise level of an operating jet engine. The apparatus comprises an exhaust nozzle including a conventional upper portion and an unconventional lower portion comprising a plurality of divergent flutes which extend axially. The flutes point away from the axial centerline of the exhaust nozzle and during operation of the engine, the exhaust gas passing through the lower portion of the overall nozzle mixes with the environmental air immediately downstream of the nozzle thereby resulting in a decrease in the noise level associated with the exhaust gases.
A Skewed Exit Plane Nozzle System for optimum thrust is described in U.S. Pat. No. 3,604,628. The physical apparatus has some similarities to the devices described above and includes a plurality of nozzles having a skewed exit plane which used in combination to maximize the thrust in a propulsion system. The nozzles are rotatably mounted about their base and each has a skewed exit plane. In an application in which four nozzles are used cooperatively, each is located ninety degrees from the other in a circular pattern and arranged with the exit plane of each nozzle essentially parallel to the direction of motion of the vehicle being propelled. Since the nozzles are rotatable the projected area can be varied with ambient pressure thereby allowing an optimization of thrust from the nozzle cluster over a wide range of operating conditions.
A generally related device which is also applicable to rocket engine technology is described in U.S. Pat. No. 3,625,435 entitled Dual Orifice Quadruplet Impingement Injector. The invention is addressed to the problems of providing thorough mixing of reactants and a uniform mixture ratio over a wide range of performance conditions. The essence of the disclosure is an injector head design wherein clusters of four openings are cooperative. The holes are formed so that the working fluid is injected at an angle to the exit plane of the injector head and at locations such that the appropriate corner hole from each of four clusters of openings arranged in a suitable pattern cooperate with each other to enhance mixing. In addition, each opening contains internal means for providing fluid intended to be mixed with a second fluid which is passed around the internal means as both fluids are expelled from the injector head.